>>Also, try ORing the WS_EX_TOPMOST style to the first param you pass to CreateWindowEx()<<

I was going to suggest that until I read (msdn):

WS_EX_TOPMOST Specifies that a window created with this style should be placed above all nontopmost windows and stay above them even when the window is deactivated. An application can use the SetWindowPos member function to add or remove this attribute.

So it seems that:

>>Call SetWindowPos(), specifying HWND_TOPMOST as the second parameter.<<